The invention relates to a constant velocity universal ball joint. The joint has an outer joint part with substantially longitudinally extending outer ball tracks and an inner joint part with substantially longitudinally extending inner ball tracks. The tracks in the outer joint part and inner joint part are positioned radially opposite one another to form a pair. In each case, the tracks jointly receive a torque-transmitting ball. A ball cage, in circumferentially distributed cage windows, holds the balls in a common plane and guides them upon articulation onto the angle-bisecting plane.
In particular, the invention relates to so-called VL joints where the tracks in the inner joint part and outer joint part form an angle in the longitudinal direction and relative to one another, which means the tracks do not extend exactly in the longitudinal direction. Joints of this type permit an axial displacement between the outer joint part and inner joint part, with the cage being guided onto half the relative displacement path. Furthermore, the invention refers to so-called Rzeppa fixed joints or undercut-free joints where the inner joint part and outer joint part are indirectly supported by a cage, via balls and cage windows, so as to be held in an axially immovable way relative to one another.
If such joints rotate in a torque-free condition, the position of the cage is indifferent. This means that, in view of the circumferential length of the cage windows, the cage when the joint is in an aligned position, is able, circumferentially, to adjust itself freely relative to the balls. When the joint is articulated, this indifferent position of the cage with its ability to freely adjust itself is only partially restricted. This degree of freedom allows the cage, to stop against the balls on alternate sides by contact of the region of its longitudinal webs between each two cage windows. The noise developing in the process is disadvantageous.
Furthermore, with joints of this type, there exists radial play between the outer face of the cage and the corresponding guiding inner face of the outer joint part, especially in the case of the cylindrical guiding faces of the outer joint part of a VL joint. In consequence, when the joint rotates in a torque-free condition, it is possible for the cage to move radially inside the outer joint part, which may also lead to a clattering noise. In the process, the cage may develop natural vibrations of high frequency. If, however, the cage rests against the outer joint part in an eccentric position, this leads to out-of-balance of the joint, which is also disadvantageous.